Constrained DFT+U approach for understanding the magnetic behaviour of ACr₂O₄ (A = Zn, Mg, Cd and Hg) compounds

详细信息    查看全文

• 作者：Sohan Lal ; ^{goluthakur2007@gmail.com} ; Sudhir K. Pandey
• 关键词：Density functional theory ; Constrained and unconstrained calculations ; Exchange coupling constant ; Curie&ndash ; Weiss temperature ; Density of state ; Band structure
• 刊名：Physics Letters A
• 出版年：2017
• 出版时间：11 March 2017
• 年：2017
• 卷：381
• 期：10
• 页码：917-923
• 全文大小：1295 K
• 卷排序：381

文摘

Inconsistent behaviour of nearest neighbour exchange coupling constant (J) predicted by Yaresko is studied in chromium spinels. Unconstrained calculations give the inconsistent sign of J and variation of its magnitude with increasing U for CdCr2O4 and HgCr2O4 for U>3 eVU>3 eV and U=2–6 eVU=2–6 eV, respectively. The sign of J and variation of its magnitude with increasing U observed in constrained calculations are consistent with experimental data and equation, J  ∝t2U, respectively. The present study shows the importance of constrained calculations in understanding the magnetic behaviour of these spinels.